JAdmiral

Yes, that's right... yesterday, driving on the freeway, my right rear wheel decided to come OFF! It stayed in the wheel well while I quickly slowed down and pulled over.

Upon inspection, it appears that four of the five hub bolts broke off inside of the hub.

My question for all of you is: What would cause that? The last place to touch my car was the tire shop when they replaced a tire (I'm still confirming whether it was the same tire).

My car dealer suggested someone OVER torqued the bolts. Possibility? If so, what are the torque specs for a wheel on the 2007 S550? Any other suggestions on how this might have happened? I don't believe I had chrome bolts, since I did have a decorative cover over the bolts.

Thanks for any help you can lend.

nielsll

Are you running MB OEM wheels and lug bolts?

JAdmiral

No... I have D'Vinci wheels. No idea about the bolts.

gsrjc

I'm not sure about D'Vinci wheels because I've never heard of them but most of the time, you need new lugnuts whenever you get aftermarket wheels because the holes in the wheels have a different style. that might have been the reason your wheel fell off. I would check with the company that you got the wheels from and see if you need aftermarket lugnuts.

nielsll

With the bolts cracking under torque I would bet that they are aftermarket and of inferior quality. Make sure you get bolts with seats to match the wheels (conical or ball), are of correct length, and of proper material and grade. Being such a simple and ubiquitous item, lugs are often overlooked. They can kill you. Know what you are using.

nrg_mike

One thing you should have also checked when buying the wheels was to see if the wheel is Hub Centric w/ the Mercedes. Often times, aftermarket wheels use a generic center hole measurement that is larger than the Mercedes center hole measurement. If the measurements are off, you'll have slight vibration in the wheel as the wheel is no longer truly centered on the hub. This will hurt your ride quality, and add added stress to the lug nuts, studs, and hub assembly. To correct this, you should look into "Hub Centric Rings". They are measured in Inner Diameter and Outer diameter (say for example, 60mm/70mm) or 52.1/64.1, etc.
Another thing to look at would be the lug nuts you have installed. If you've got aftermarket lug nuts, they're often sand cast or mold cast aluminum that aren't as strong as the standard OE ones. Also, for the lug nuts, you need to make sure you've got the proper seat type, thread length, and thread size.

Tightening torque for your lug bolt should be 110 lb/ft or 150nm.